Picked up a 1985 RX7 for 850 bucks a few weeks ago, and the guy had parts and stuff in the back. I believe it is the anti afterburn valve? that is broken off, but the engine likes to backfire if i let go of the gas, when i turn off the car, and if i punch it, when i shift up. (It only usually pops once, but occasionally on the highway it will backfire if I try to accelerate) It is a metal rod that goes from the engine compartment to about halfway under the car, to, I believe, the catalytic converter. Sorry, only my second car, and first rotary. Just wondering where i could find a new one (or should i just go to a pick n pull?) or if I would have to get the old one like welded back on, its sheared off.

 

Sounds like the split air pipe and the ACV.

If they were removed, the cats also would have to be removed as well as the air pump. If the cats are still there then they will clog in short order.

 

good find rx7 is great fun.

 

Having an exhaust leak also makes backfiring much more likely, so if the tube is sheared off the exhaust and letting fresh air into the exhaust- BANG!

 

Here are some pics of the pipe that is sheared off.

http://img5.imageshack.us/my.php?image=may09049.jpg


http://img5.imageshack.us/my.php?image=may09048.jpg


http://img5.imageshack.us/my.php?image=may09047.jpg

 

Also, recently the car will not start, I've tried getting it jumped, and it will start when connected to another vehicles battery, but i ran it at about 2k rpms for 20-30 minutes to charge the battery. I shut it off, tried to start, and the battery power just cut when I tried to start it, and the battery now cuts when the key is in the "on" position, no lights on the dash, fans cut out, everything... I'm assuming this is a short in the ignition?

 

That's the split air pipe. If you have cats, you need it.

Check the condition of the battery cables. They like to corrode and cause poor connections at either the battery or the other end (chassis, starter, fuse box, etc.).